NullPointerException, at javax.swing.ImageIcon.<init>(Unknown Source)

[mydavor]

THIS PIECE OF CODE SUDDENLY STARTED FAILING FOR SOME IMAGES, IT USED TO WORK FINE. THE IMAGES ARE AVAILABLE, AND THE SAME STUFF WORKS PERFECTLY WHEN ACCESSED FROM A REMOTE BOX.

AT FIRST I SUSPECTED ON MISSING JAR, SO I CHECKED MY CLASSPATH MANY TIMES, BUT NO, IT FAILS ONLY FOR A FEW IMAGES - YET I COULD NOT SEE ANY DIFFERENCE BETWEEN UNSUCCESSFUL AND SUCCESFUL IMAGES - AGAIN, EVERYTHING WORKED SMOOTHLY TILL YESTERDAY.
private java.awt.Image loadImage(String name){
try {
DPUtility.println("DPDataSelection -- loadImage 1"); // SB
java.net.URL url = getClass().getResource(name);
DPUtility.println("DPDataSelection -- loadImage 2"); // SB
return createImage((java.awt.image.ImageProducer)url.getContent());
}
catch(Exception eLoadImage){
DPUtility.println("DSB :\t ERROR :> DevPro - Image could not be loaded: " + name);
eLoadImage.printStackTrace(); // SB
return null;
}
}



HERE FOLLOWS THE OUTPUT:

DPDataSelection -- loadImage 1
DPDataSelection -- loadImage 2
DSB : ERROR :> DevPro - Image could not be loaded: trying.gif

java.lang.NullPointerException
at devpro.beans.DPDataSelection.loadImage(DPDataSelection.java:286)
at devpro.beans.DPDataSelection.<init>(DPDataSelection.java:226)
at DPRFTApplet.<init>(DPRFTApplet.java:435)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at java.lang.Class.newInstance0(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at sun.applet.AppletPanel.createApplet(Unknown Source)
at sun.plugin.AppletViewer.createApplet(Unknown Source)
at sun.applet.AppletPanel.runLoader(Unknown Source)
at sun.applet.AppletPanel.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
java.lang.NullPointerException
at javax.swing.ImageIcon.<init>(Unknown Source)
at devpro.beans.DPDataSelection.<init>(DPDataSelection.java:226)
at DPRFTApplet.<init>(DPRFTApplet.java:435)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at java.lang.Class.newInstance0(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at sun.applet.AppletPanel.createApplet(Unknown Source)
at sun.plugin.AppletViewer.createApplet(Unknown Source)
at sun.applet.AppletPanel.runLoader(Unknown Source)
at sun.applet.AppletPanel.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

 

[mydavor]

NOTE THAT ALL THE IMAGES ARE IN classes/images and WEB-INF/images, THEY ARE also in a .jar file.
should they be in the jar file ?

 

[sedj]

PLEASE DON'T SHOUT !!!

I would suspect that the "name" or path of the resource you are try to locate is not correct.

Consider this code

public class Test {
 	public static void main(String args[]) throws Exception {
		System.err.println(new Test().getClass().getResource("Test.java"));
	}
}

Then jar up your class and Test.java into a jar file :

jar -cvf test.jar Test.class Test.java

and set your classpath to point only at the jar file :

set CLASSPATH=C:\java\test.jar

and then execute the class, you will see this :

C:\java>java Test
jar:file:/C:/java/test.jar!/Test.java

Now make a new directory, move the Test.java to it, and rejar :

C:\java>mkdir tmp

C:\java>xcopy Test.java tmp
C:Test.java
1 File(s) copied

C:\java>jar -cvf test.jar Test.class tmp/Test.java
added manifest
adding: Test.class(in = 590) (out= 378)(deflated 35%)
adding: tmp/Test.java(in = 26586) (out= 6754)(deflated 74%)

and when you run the class again, you will get this :

C:\java>java Test
null

So from this, you can see that paths are very important when finding resources relative to the code's execution directory.

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